Studies are in progress to determine the effect of selenium on dental caries in the rat model. Such experiments will utilize both high (67%) and moderate (20%) sucrose diets, oral innoculations with S. mutans-6715, and injections of selenium to suckling rats. Caries will be scored on the mandibular molars. These experiments will attempt to develop an animal model for studies to elucidate the relationship of selenium to dental caries.